.\" Copyright (c) 2003 David Schultz <das@FreeBSD.org>
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.Dd February 12, 2003
.Dt ISGREATER 3
.Os
.Sh NAME
.Nm isgreater , isgreaterequal , isless , islessequal ,
.Nm islessgreater , isunordered
.Nd "compare two floating-point numbers"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In math.h
.Ft int
.Fn isgreater "real-floating x" "real-floating y"
.Ft int
.Fn isgreaterequal "real-floating x" "real-floating y"
.Ft int
.Fn isless "real-floating x" "real-floating y"
.Ft int
.Fn islessequal "real-floating x" "real-floating y"
.Ft int
.Fn islessgreater "real-floating x" "real-floating y"
.Ft int
.Fn isunordered "real-floating x" "real-floating y"
.Sh DESCRIPTION
Each of the macros
.Fn isgreater ,
.Fn isgreaterequal ,
.Fn isless ,
.Fn islessequal ,
and
.Fn islessgreater
take arguments
.Fa x
and
.Fa y
and return a non-zero value if and only if its nominal
relation on
.Fa x
and
.Fa y
is true.
These macros always return zero if either
argument is not a number (NaN), but unlike the corresponding C
operators, they never raise a floating point exception.
.Pp
The
.Fn isunordered
macro takes arguments
.Fa x
and
.Fa y
and returns non-zero if and only if any of
.Fa x
or
.Fa y
are NaNs.
For any pair of floating-point values, one
of the relationships (less, greater, equal, unordered) holds.
.Sh SEE ALSO
.Xr fpclassify 3 ,
.Xr math 3 ,
.Xr signbit 3
.Sh STANDARDS
The
.Fn isgreater ,
.Fn isgreaterequal ,
.Fn isless ,
.Fn islessequal ,
.Fn islessgreater ,
and
.Fn isunordered
macros conform to
.St -isoC-99 .
.Sh HISTORY
The relational macros described above first appeared in
.Fx 5.1 .
